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My Polk SDA 2B journey....

Impressions after another day: The most striking difference I have noticed so far is how much better the bass response. The lower range sounds more full, and conveys more impact. At this point I am only using my sub for LFE as stereo music no longer requires reinforcement of the lower frequencies. So far I am thrilled with the results!
 
Johnny_Law said:
Congrats! Great to read how well they responded to the mods.

The two things I highlight from your post - dynamat and sound deadening behind mids. I found these mods to be rewarding in my previous Polk restorations. Would recommend them!
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Both are on order along with new boards for these and the 1Cs that I am now working on.
 
I swapped the cs400i and csi40 to end up with the 400i in the living room. I think I like the sound from it better....

Also just passed on a cs350 ls that was FS local to me for $100. It is relisted and I may pick it up to compare if I cna get it for about half what it is currently listed for.
 
H-Nuts went in a week ago, at the time all I had was some 8-32 button head machine screws.
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I really didnt like the way the looked at all.
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Spent some time poking around on McMaster Carr and settled on some beveled 1" 8-32 course thread for the tweeters and zome 7/8" 8-32 cap machine screws for the drivers and PRs. I believe all are course thread.
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I can find the links if anyone wants them, but I am on my phone now so I will have to add them later.
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To update I swapped in new crossover boards (same components). Replaced the LF coil with new inductors on both sides. Dynomatted the baskets, added BH5 behind the mids, replaced the damaged gaskets and oiled the wood top and bottom. The result was just more of the same. I had them set up for a while as I set up my man room in the new house. I could happily live with these speakers for a long time. I would keep them in the main rig if I hadn't found a pair of mint one owner SDA SRS 2.3tl a few weeks before I moved from SD to Maryland. I will do the full range of mods on the 2.3s over the next several months. While that is going on I will leave the 2Btl set up. I may take this chance to A/B the 2B and 1C. I suspect the end result will be putting the 1C up for sale....
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Navy_Goat said:
My initial impression after 15 to 20 hours:

I have to start by saying I have no accurate back to back listening as I have had my 1C's set up for the last month or so. I would bet that my experiences are represent the switch from un-modded 1C to modded 2B more than a direct comparison of before and after for the 2B.

Highs: I remember the highs being very detailed after the initial mods (RD0198 + 5.8 uF cap = minimum TL mod). So far the highs still sound detailed and engaging.

Lows: Bass seems to be filled in a lot more. This is the biggest improvement I hear at this point. I am playing them without my sub and I don't miss the sub at all.

Overall: As @F1nut already stated, I think I will end up enjoying these at least as much as the 1C. They just present a very balanced sound. I will likely be modding the 1Cs next to see where they end up with new caps, resistors and RD0194s, but I will not be surprised if these 2Bs continue to outperform their larger brothers.

I am curious how much can still be gained by replacing the last few components and finishing all the suggested mods. If I want to continue, the following upgrades are still not done:

- Inductors
- Seal the corners of the cab and seal the rear connector assembly (drivers and PR are done)
- Internal wiring
- Binging posts
- Switch interconnect to speakon connectors
- Dynamat
- BH5 behind mids

Any input on the likely results of completing any of the mods above would be welcome.

Time will tell how much farther this goes. At this point I am happy with the progress and really enjoying the sound.
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I looked and looked, but can not find the (true) frequency response specs of your speaker. I mean the -3db that is typically used, not the -10 or more db that Polk specified on some of their literature back in the day.

Some spec sheets showed both, but on the SDA 2B never found the much more accurate -3db spec, but from memory I believe it was in the mid 30 Hz range.

I do remember from memory back in the later 80's when I would demo the Polks, the Rta11t had a very similar deep bass, and due to its narrow footprint and lower price would often be the one several customers chose.
 
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Mid to high 30s sounds right. I wonder if anyone has measure them after performing all the standard mods? I wouldn't expect a huge change in measurements. Sound quality improved significantly. Part of the difference I am hearing will be due to the NAD amplifier I am using to drive them. It has a distinct signature that was only enhanced when it was refreshed recently. Its hard to say which changes are responsible for the change.

I can tell you I really like the result and that's what is most important.

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Currently living in my 2 channel room with a pair of Zu Audio Omen Dirty Weekends. Both sound great, both are capable of completely filling the room.

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Now I need to find some more decorations for the room. So far I have hung a few work related items. I need to look for some audio related pictures and such.
 
Having a friend make matching challenge coin displays for the top of both 2Bs. HE is going to try to match the wood as close as possible. This may not work at all due to vibration, but worst case I have a matching pair of coin displays for my desk at work. Its a friend doing the work so this $$ is reasonable.

What is not reasonable is the amount of $$ I just dropped to upgrade my larger Polks to the same level of these 2Bs. But that is a story for anoteher thread
 
Bkphoto said:
Nice work, SDA is definitely an acquired taste...not my thing but definitely respect the quality and tech..
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I have to agree. Was never my thing either, but an interesting idea none the less.

Decades ago when I sold to customers, everyone wanted to hear the bigger models of course, and some bought them, but most tended for a variety of reasons to stick with the Non SDA models, and I believe the M10 was probably the best selling of that time.

I always preferred the M7 and Rta11t for actual sound quality. Even compared to the SDA models.
The bigger SDA models would go a bit deeper and louder for sure, but being able to compare them side by side, thought some of the Non SDA models actually excelled in clarity and imaging.
 
kevintomb said:
I have to agree. Was never my thing either, but an interesting idea none the less.

Decades ago when I sold to customers, everyone wanted to hear the bigger models of course, and some bought them, but most tended for a variety of reasons to stick with the Non SDA models, and I believe the M10 was probably the best selling of that time.

I always preferred the M7 and Rta11t for actual sound quality. Even compared to the SDA models.
The bigger SDA models would go a bit deeper and louder for sure, but being able to compare them side by side, thought some of the Non SDA models actually excelled in clarity and imaging.
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I have a small pair from the monitor line (5jr) and they sounds wonderful. I have not heard any of the others in the monitor line but I would expect them to be more of the same, which is pretty good. I would be surprised if any of the monitor line outperformed the even the smaller SDAs. I do know that the SDAs are not easy to set up (need the right room and placement) and very hard to drive. I wonder if that played a part in your experience? Lots of the components were shared through both lines as the production dates matched for a wile, so all things being equal the sound should be very similar. I just find it hard to believe that Polk was taking step backwards in terms of sound as they brought new products to the market.

I am definitely looking for any sort of internet squabble, but I would be happy to continue to discuss here. I just saw a set of M10 (not sure which version) on CL for 80 bucks. If I didn't have enough on my plate at this point I would have picked them up.

In the end it doesn't really matter, there is plenty of room in the world for everyone to like different things. Wouldn't it be boring if we all wanted exactly the same thing?
 
Navy_Goat said:
I have a small pair from the monitor line (5jr) and they sounds wonderful. I have not heard any of the others in the monitor line but I would expect them to be more of the same, which is pretty good. I would be surprised if any of the monitor line outperformed the even the smaller SDAs. I do know that the SDAs are not easy to set up (need the right room and placement) and very hard to drive. I wonder if that played a part in your experience? Lots of the components were shared through both lines as the production dates matched for a wile, so all things being equal the sound should be very similar. I just find it hard to believe that Polk was taking step backwards in terms of sound as they brought new products to the market.

I am definitely looking for any sort of internet squabble, but I would be happy to continue to discuss here. I just saw a set of M10 (not sure which version) on CL for 80 bucks. If I didn't have enough on my plate at this point I would have picked them up.

In the end it doesn't really matter, there is plenty of room in the world for everyone to like different things. Wouldn't it be boring if we all wanted exactly the same thing?
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I liked the M7, the 5jr+, and the Rta11t best.

I simply never cared for the Crosstalk cancellation on all types of music, but I think the overall SDA speaker "line" sounded very good otherwise.
I had customers all over the place about the SDA thing. Some loved it, some hated it, some could not even tell if it was different or better or worse overall. Some wanted to bring certain music to test it, some laughed it off as just a gimmick. Reactions were all over the place.

It is a very listener dependent thing for sure, and frow my sales experience and online forums, some love it, some not so much.
 
kevintomb said:
I liked the M7, the 5jr+, and the Rta11t best.
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I believe the 5jr+ and 11t both feature the later SL2500 or SL3000 tri-lam tweeters. Those tweeters are much better than the earlier SL line. Night and day difference. I would have preferred a pair of the 5jr+ for exactly that reason. I did replace the tweeters in my 5jrs with the current drop in replacement which is much better than what it came with. Overall, I am happy enough. They are in the garage running off a Yamaha WXC-50 with an Adcom GFA-535 providing power. They are not going to blow you away with bass, but otherwise sound pretty damn good.
kevintomb said:
It is a very listener dependent thing for sure, and from my sales experience and online forums, some love it, some not so much.
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This matches what I have seen online. I just wonder how many of those listeners were listening to a set that was not placed well, or driven by an underpowered amp (any AVR for example). Those two factors can really compromise even the smallest SDAs. That is a legitimate downside to these old Polks.

When I initially set up my stereo in the new house I put all the Polks (2.3tl, 1C and 2Btl) in a spare bedroom upstairs. I planned to set up a pair of Zu Audio Dirty Weekends in the living room because my wife really prefers the way they look and I like the way they sound well enough.
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Immediately I could tell that something was very wrong with the way the 2.3s sounded. The room was just too small and I dont think I could have done anything to fix it. In that room the 2Btls just sound better. I moved them down the the large living room and they are back to sounding great. At this point they have 8ft of clearance on both side so they sound better than ever.

This experience really demonstrated to me how important proper placement in the right room is.
 
Yes the room and placement factor in a great deal with the Crosstalk cancellation, I agree totally.

I think when discussing the "SDA" line of speakers, there are 2 qualities, that are distinct but at the same time both contribute to the sound.

1. The actual tonality, and frequency response and distortion etc.

2. The crosstalk cancellation "feature/idea/effect"

I really liked the overall speakers sound and bass and output, but simply no matter what placement spacing found the crosstalk cancellation not to be a "Plus" on all musical recordings.
To me, I found it very hit and miss. Some music better, some not so sure, and some to me it degraded what I thought the sound should be.

Beyond placement and room size etc, I think some people are "Wired" (pun intended) to like that sound, and some simply do not. I never hated it, nor loved it, but was always unsure what I truly thought. I would often listen to the same song on my SDA's and then go to a conventional speaker, and find the conventional "better" in regards to soundstage.
Do not want this to sound negative, as I really liked them, but maybe not in all ways.

Fyi, Rta11t used the SL2000 Tweeter, it was not until the last year or so of the Rta they changed to the newer tweeter. I think 1990-1991 if I remember correctly.

As with everything, I remember reading online arguing over if the new or old tweeter was better, but concluded it depended on if the listener had flat or rolled off hearing on the high end.

Like anything, views all over the place!
 
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It's best to compare what SDA presents to a live musical performance. That's when it becomes obvious SDA is as close to live as you'll get in your listening room.
 
I would agree that SDAs do not compliment poor recordings at all. Recordings that are less than good seem to be missing something? Hard to describe exactly, for me anyway. I have had 3 pairs of SDAs and one set of Zu Audio speakers in the house over the last few years, so I don't have much to compare them to. The Zu speakers sound totally different. They have virtually no crossover and are very close to full range (tweeter handles above 12k only). Basically the polar opposite of the multi driver, complicated crossover design of the Polks. I have both the SDA-2B and Zu Dirty Weekends set up in my small listening room so I have the ability to compare them back to back. I like them both, but they do sound very different.
 
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I have a pair of Monitor 7s (rebuilt x-overs) with Peerless tweets next to SDA2s that are unmolested, save for the SDA effect tweet disconnected and to my ears, the M7s only give up a bit on the low end. It's very easy to a/b them. I sold a pair of SRS 3.1 TLs with RLO198 tweeters to a friend and they were the best of the three I mention. Why I sold them, not quite sure. I still have regrets though.

I also have a pair of Polk LS50s that are augmented with a Velodyne servo sub. Not a fair comparison but this system sounds the best, especially with modern music that contains deep bass but for obvious reasons.
 
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